The invention relates to a method of placing a web on an entrenchment below the ground water level. Usual methods of placing such a web consist of first draining the entrenchment at the start of a constriction project so that the web can be placed in a simple way. Draining the water does however also affect the ground water level in the area outside the entrenchment and therefore, draining is not always allowed at the beginning of a constrication project. A typical example is an entrenchment for a road near a wildlife habitat.